UNIX SPECX distribution via WWW

UNIX Specx is still under development and a number of enhancements and bug fixes have been incorporated in the JACH distributon. In fact, all attempts are being made to keep the distribution up-to- date continuously. For this reason the distribution may also be of interest to Starlink sites which can not wait for an update via the regular mechanism.

Standalone Specx can be obtained using Mosaic to the 'James Clerk Maxwell''section of the JAC WWW pages (http://www.jach.hawaii.edu), topic 'Unix Specx':

URL : ftp://ftp.jach.hawaii.edu/pub/jcmt/specx

Alternatively, the relevant files can be obtained via anonymous ftp from ftp.jach.hawaii.edu (log in as `anonymous', password your e-mail address) in directory pub/jcmt/specx:

Once connected, type (or use the above entry via Mosaic etc)

ftp> cd pub/jcmt/specx

ftp> get AAAREADME

ftp> get INSTALL_SPECX

and follow instruction therein.

Users are encouraged to 'register' with me (rpt@jach.hawaii.edu) once they have installed Specx (see WWW page). Registered users will be notified of major bug fixes.

Enhancements

A list of some of the more major enhancements of the standalone version with respect to the current Starlink distribution:

incorporated in standalone Specx is a sophisticated command-line user interface developed by the GNU consortium (the Readline library distributed with the Bash shell). This interface supports the regular arrow-keys editing of the history, a large number of Emacs-like control-key commands (can be changed to Vi-like appearance), plus features like a TAB-key expansion of filenames and support of keyboard macros.

a signal-handler has been added to the standalone version which traps ctrl-C's and arithmetical errors. A ctrl-C will abort the current Specx function and put you back at the Specx prompt, similar to the VMS version. This feature is not completely full-proof, but appears to work under most conditions.

standalone Specx uses the newest version of Caltech's plain-vanilla PGPLOT distribution. It supports many new devices such as GIF files.

the standalone version correctly writes 4-Byte FITS files, instead of 2-Byte FITS which can lead to digitization errors. The FITS keyword list has been enlarged for better support of Specx FITS files under AIPS.

plus a number of minor Bug fixes (e.g. FIT-GAUSS).

My impression is that the standalone version of Specx is much more robust than the current Starlink version, although more work is needed. One particular major bug in all Unix distributions which needs

to be fixed before making a new release to Starlink is associated with use of the HDS files.

WARNING: ANNOYING BUG IN UNIX SPECX

The UNIX version of Specx has adopted the HDS format for its native file format (hence the .sdf files). Unfortunately the way Specx uses its files, namely as continuously open buckets to which spectra are added or from which spectra are read, causes the files to be corrupted in the event Specx exits abnormally (e.g. crashes). This problem is under investigation by Rachael Padman and the best advice for now is to keep backup copies of the most important files otherwise you will probably find yourself in the tedious situation of having to redo yesterday's work.

One change which helps, but not fully fixes the problem is to add the following lines to the $SYS_SPECX/specxstart script:

#

# TEST: Disable HDS mapping in favor of R/W mode

#

setenv HDS_MAP 0

Remo Tilanus, JAC

(rpt@jach.hawaii.edu